To express changes..

Use the Future Perfect tense to express changes you think will definitely be possible or will happen in the future.

By 2030, smartphones will have replaced most traditional landlines for communication.

Example:

Subject + will have + V.3

1

Future Perfect

We often use conjunctions to indicate that an action will be completed before another action or a specific time in the future.

By the end of this year, Engineers will have developed even more sophisticated AI translation tools

Example:

By - Before - By the time - By the end of

To express changes..

Use the Mixed conditional to express results or consequences of past actions/developments which has effects in the present.

If mobile phones hadn't been invented, we wouldn't be able to communicate instantly from anywhere in the world today.

Example:

If + past perfect (had + past participle), would + V.1 (or could/might/should).

2

The old rotary phone and the new smartphone are very different. If we hadn't developed mobile technology, we would still be using phones with cords today. By now, smartphones will have replaced almost all home phones in many countries. If people had needed to stay home to make calls, daily life would be much harder. Soon, even more advanced phones will have changed how we communicate again.

In the future, new phones will have done even more things for us. If we had used rotary phones for travel, our bags would be very heavy. By 2030, phones will have helped us connect in ways we can't even imagine now.

​Put them in use - Example